Unveiling Methylobacterium sp. 2A plant growth-promoting abilities and auxin signalling modulation for enhanced plant development.

GROSSI, CECILIA EM; TANI, AKIO; ULLOA, RITA M

Kochi

Conferencia; Japan Branch Joint Conference, 100th anniversary of the founding of the Japanese Society of Agricultural Chemistry 2023; 2023

Japan Society for Bioscience

Methylobacterium sp. 2A, a pink-pigmented rhizobacterium induces positive changes in Arabidopsis thaliana development and synthesizes IAA. We measured phytohormone levels in strain 2A-inoculated A. thaliana. JA and SA increased upon inoculation, while IAA levels remained unchanged. Strain 2A-inoculated plants displayed typical auxin-dependent phenotypes. The auxin-responsive DR5 promoter activity was detected in root tips and lateral root emergence sites upon inoculation. Furthermore, the functional impact of 2A-secreted IAA on root architecture was investigated in yucQ, iaa19, arf7, and arf19 mutant seedlings with reduced lateral root formation. After 7 days, inoculation with 2A resulted in a significant increase in lateral root density in all mutants. These findings strongly suggest that 2A modulates root architecture through the secretion of IAA.